A software defined networking (SDN) technique has been known in which for the purpose of quickly executing, for example, a change of route setting on a network (hereinafter, simply referred to as NW), a communication device is specified in a simple transmission function, and the operation of the communication device is unitarily controlled by a control device. However, in the SDN, when the control device is implemented with one server, the function of the control device may not keep up with the expansion of the NW scale.
Thus, in a distributed communication control system, a plurality of control devices having the same function are provided, and each of the control devices undertakes a control of each communication device within the NW. Of the plurality of control devices, a control device responsible for a control of a communication device is called a master control device. In the distributed communication control system, the master control device is dynamically changed, for example, in order to distribute the load of the control devices. In addition, the distributed communication control system may include an open network operating system (ONOS).
Process functions executed by a control device within the distributed communication control system include a route setting to set a route on a NW and a failure recovery to restore a failure of the route. The route setting sets transmission setting information in a communication device on a route, in order to establish a route between sites (or terminals or the like) connected to a NW according to a request from a user or an operator of the NW. As for the failure recovery, when a failure occurs in the set route, in order to restore the failure, a detour of the failure on the route is calculated so as to ensure the continuance of the communication between the sites.
Related technologies are disclosed in, for example, Japanese Laid-Open Patent Publication No. 2012-169889, Japanese National Publication of International Patent Application No. 2015-508622, and Japanese Laid-Open Patent Publication No. 2008-054233.